Rate changing mechanism



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I. E. MATHE R ETAL RATE CHANGING MECHANISM File d Dec 27. 1943 Feb. 25, 1947.

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RATE CHANGING MECHANISM Filed Dec. 27, 1943 s Sheets-Sheet s .(JQWW/W W a W 5 l: J 1 q 3H 3 Patented Feb. 25, 1947' UNITED STATES PATENT o en RATE CHANGING MECHANISM Irwin E. Matherand Arthur C. Allen, Chicago, and Stanley J. Budlane, Moline, 111., assignors to Stewart-Wamer Corporation, Chicago, 111., a corporation of Virginia Application December 27, 1943, Serial No. 515,714

9 Claims. 1

order that the fuel supplied to an engine, internal combustion heater, or other fuel compensating device will be properly proportioned to the combustion air for all variations in temperature and altitude.

An object of our invention is to provide a rate changing mechanism which can be utilized to modify the position of a fuel control valve or pointer to compensate for the effect of rapid changes in altitude and temperature.

Another object of our invention is to provide a rate changing mechanism which is capable of general application.

Another object of our invention is to provide a new and improved rate changing mechanism which is accurate, simple, light in weight, compact and inexpensive.

Another object of our invention is to provide a new and improved mixture control device.

Another object of our invention is to provide a new and improved air speed meter.

Other objects of our invention will become apparent as the description proceeds.

In the drawings:

Fig. 1 is a sectional view of a mixture control device embodying our'invention;

Figs. 2, 3, 4, 5 and 6 are partial, horizontal sections taken respectively on the lines 2-2, 8 -3, 4-4, 5--5 and 8-8 of Fig. 1;

Fig. 7 is a somewhat diagrammatic representation of an air speed meter embodying our invention;

Fig. 8 is a detail of the air speed indicating bellows and is taken on the line 8-8 of Fig. 'l; and

Fig. 9 is a partial, sectional view taken on the line 8-8 of Fig. 7.

The mixture control device shown in Fig. 1 comprises a tubular body l0 closed at one end by a plate l2 secured to the body by screws H. A casting I8 is attached to the plate l2 by screws 18 and a flexible diaphragm 2ll.-is firmly clamped phragm 28 and partition 22 forming a part of the casting l8 cooperate to provide achamber- 24 communicating with a fuel outlet 26 leading to a Pip 28 which furnishes fuel to an internal com-.

bustion heater, internal combustion engine, or other fuel burning device.

The screws I8 also hold in place a ring and a cap 82, the latter being provided with a fuel inlet 84 to'which fuel is supplied by a pipe 88 leading from a fuel tank, or any other suitable source of fuel. A flexible diaphragm 88 is clamped between the cap 32 and ring 80 and a diaphragm 40 is clamped between this ring and the casting It. A fuel inlet chamber "is formed between the cap 32 and upper diaphragm 88 and a valve chamber 44 is formed between the lower diaphragm 40 and partition 22. The chambers 42 and 44 are connected by a passage 48, so that fuel may freely flow past the diaphragms 88 and 40.

The partition 22 is provided with an opening 48 terminating in a valve seat ill adapted to be engaged by a tapered surface 52 of a valve member 54. A disc 58 is located between the central portions of the diaphragms 88 and 40 and this disc, valve member 54 and washer 58 are at-' tached to these diaphragms by a pin 80 whose upper end is riveted over'the washer 58, as clear- 1y shown in the drawing.

The fuel inlet chamber 42 has a slightly smaller diameter than the intermediate chamber 44 and this diflerence in diameter reflects the differences in effective areas of the diaphragms 38 and 40.

The area of the diaphragm 40 is greater than a the area of the diaphragm by an amount equal to the area of the valve seat, 50. By virtue of this construction, fluid in intermediate chamber ing through the diaphragm 20 and extending through openings in a pair of washers 84 clamped on opposite sides of the central portion of this diaphragm. A pin 68 pivotally connects the extension 62 to the upper end of an operating link 88. In general, the operating link 88 and valve member 54 are controlled by a main diaphragm l0 clamped between the body Ill and a cover 12 attached to the other end of the body Ill by screws 14. An air pressure chamber 18 is provided between the diaphragm Ill and cover 12 and this,

between the casting l8 and plate It. The dia- 66 chamber communicates with a combustion air ram by way of pipe 18, so that the pressure in the chamber I8 varies with the force available tosupply combustion air to the internalcombus I tion heater, engine or other fuel consuming apparatus. Since the mass of air supplied to such apparatus varies with the temperature of the air and the barometric pressure, we have provided means interposed between the diaphragm I and link 88 for changing the relationship between valve member 54 and diaphragm I0 in accordance variation-s in temperature and barometric or atmospheric pressure.

Plates 80 and 82 are secured to diaphragm I0 by a rivet-like extension 84 of the plate 80 which extends through diaphragm and plate 82 and is riveted over, as clearly shown in the drawing. The plate 80 has a boss 88 pivotally connected by a pin 88 to a second operating link 90.- Nut and bolt 92 pivotally connect the upper end ofithe link 90 with oneend of a lever 94 ful crumed about a pin 98 supported in brackets 98 attached to the body I0 by bolts I00. The other end of th lever 94 is provided with a slot I02 'slidably receiving a pin I04 mounted in a slide I08. The slide I08 has a rectangular opening I08 through which the pin 98 passes. -The length and width of this opening I08 are such that the slide I08 may shift the pin I04 lengthwise of the slot I02 and may also pivot to some extent about this pin without engaging the fixed pin 98.

The righthand end of slide I08 is of reduced cross section'and terminates in a ball I I 0 univer.

sallymovable in a socket II2 riveted to the inward extension I.'I4 of a plate-H8 attached to and closing one end of an evacuated be'lows II8.

The other end of the bellows H8 is sealed by a second plate I and a spring I22 confined between plates H8 and I20 tends to expand the v bellows II8 against the resistance of atmospheric .ends; are pivotally connected to brackets 98 by links I32 and I34. The vertical position of the floating members I is in general determined by the position of th diaphragm "I0, but for any given position of this diaphragm, the vertical position of floating members I30 will vary with variations in atmospheric pressure through ex pansion and contraction of bellows "8. Such are fllled with a fluid whose volume changes ma.-

the center. of

I42 having a boss I44 forming a universal socket for a ball I48 formed at one end of a second slide I48. The cup I38 and bellows I form a fluid chamber I50 which communicates through a tube I52 with a bulb located on the wing of the aircraft, or in any other exposed position where it is subject to variations in atmospheric temperature. This bulb, the tube I52 and chamber I50 terially with temperature variations whereby increases in temperature move slide I48 to the right. 7

as viewed in the drawings and decreases in temperature permit bellows I40 to expand and move this slide to.t he left.

As clearly shown in Figs. 1 and 3, the slide I48 carries a pin I54 located in slots I58 in floating members I30 and in a slot I58 of a lever I80 pivoted about a pin I82 mounted in the brackets 98.

- Nut and bolt I84 form a pivotal connection beexpansion and contraction produce a corresponding movement of the slide I08 which shifts pin I 047 closer to or farther from the fixed pin 98 which-forms the fulcrum for the lever 94 A drop in atmospheric pressure permits bellows II8 to expand, thereby moving pin I04 away from fulcrum pin 98 and increasing the movement of floating members I80 for a given movement of;

diaphragm I0. Conversely. an increase in atmospheric pressure will produce a contraction of bellows H8 and reduce the movement of floating members I30 in response to movements of the diaphragm I0. A second cup I38 is threaded into the tubular body I0 and located in place by a nut I38. A bellows I40 has one end sealed to the open end;

of the cup I38 and the'other end sealed to a late tween th lever I and lower end of the valve operating link 88. The slide I 48,-therei'ore, controls the point of pivotal connection between the floating members I80 and the'lever I80, so that an increase in temperature moves the pin I54 closer to the fulcrum I82 and increases the effect of movements of diaphragm I0 on the "fuel con-- trol valve member 54, whereas a decrease in temperature decreases the effect of such diaphragm movements on the fuel controlvalve.

From the foregoing description of that form of our invention shown in-Figs. 1 to. 6, inclusive, it will be apparent that we have provided rate changing mechanism which modifies the eil'ect of movements of the main diaphragm I0 on the fuel control valveto compensate for changes in atmospheric temperature and altitude. A decrease in temperature is accompanied by an increase in the density of the air at agiven atmospheric} pressure. The increased density 01' the air tend:

unduly to raise the main diaphragm I0 so that v the temperature responsive slide I48 reduces the eflect of diaphragm movements on the fuel valve with decreases in atmospheric temperature to compensate for the over lifting of the diaphragm I0 by the increased mass of the air entering the ram which is connected to the diaphragm chamber I8 by way of pipe I8.

' 0n the other hand, a decrease in the atmospheric pressure tends unduly to lower the diaphragm 10 and to compensate for this the bellows II8 moves slide I08 to increase the effect of d aphragm movements on the. fuel valve. By virtue of our novel rate changing mechanism a proper .ratio of fuel to combustion air is maintained under all variations of temperature, altitude and speed.

In the embodiment of Figs. 7 to 9, inclusive, we

have illustrated a modified form of our rate changing mechanism as being applied to an instrument for indicating the air speed of an air-.

craft. This air speed indicator is shown as comprising a stationary dial I5I which may be marked with suitable indicia representing different air speeds and a movable pointer I53 which is rotated over the dial I5I by a shaft I55 to which the pointer is attached. A gear I 81 is secured to the shaft I55 and is driven by a segv mental gear I59 rotatable about a fixed pivot I8I.

A floating member I83 lspivotally mounted on a portion of the frame by means of a pin I85 and has a slot I88 receiving a pin I 88 carried by an L-shaped link "0 pivotally attached at I12 to t the movable end of an evacuated bellows I14 havins a spring I I8 tending to expand thebellows against the force of atmospheric pressure. The" pin I88 also extends into the slot I18 of a driving arm I88 attached to a rotatable shaft 182.

The. shaft I82 is rotated by an air speed responcontraritions thereof. This plate carries a ring I82 having balls I84 located in sockets formed 1 therein. These balls also have portions located in inclined cam grooves I88 formed in the shaft I82 which is to be held by any suitable means against longitudinal movement so that expansion andcontraction of the bellows I84 shall cause rotation of the shaft I82 andyarm I88 attached thereto.

The extent to whichthis rotation of arm I88 is transmitted to floating memberl88 depends upon the position of the pin I88 in the slots I88 and I18. The position of this pin varies with atmospheric pressure which controls the expansion of the evacuated bellows I14. A decrease in a atmospheric pressure results in expansion of the bellows I14 and movement of the pin I88 to the right, as viewed in Figs..7 and 8, thereby increasing the effect on floating member I83 of movements of arm I88. An increase in atmospheric pressure produces a contraction of bellows I14 and a leftward movement of pin I88, which decreases the eifect of speed changes on the position of the floating member I63. i

Floating member I83 also has a second slot I88 arranged at right angles to the slot I88. A pin 288 is slidable lengthwise of the slot I88 and also of a corresponding slot 282 formed in the segmental gear I58. The pin 288 is mounted on the upper end 01' an L-shaped link 284 pivoted at 288 to one end oi! a U-shaped strap 288 attached to the free end of a bellows 2I8. The opposite end of the bellows M8 is attached to a fixed support 2 I 2 which may be part of the instrument housing and may constitute the sama structural element wh ch SunDoltSf the lefthand end of the evacuated bellows I14.

The bellows 2| 8 elongates and contracts with variations in temperature and is fllled with .an

expansible fluid and connected by a tube 2 I4 to a I temperature bulb located on the wing or other exposed part of the aircraft. The temperature responsive bellows 2I8 controls the position of the pin 288 and thereby varies the pivotal relation ship between the floating member I88 and seg-' mental gear I59 to compensate for the effect of temperature variations.

From the foregoing descr ption of that form of our invention embodied in Figs. 7, 8 and 9, it will be apparent that we have provided an air speed indicator which is compensated for the effects of variation in atmospheric temperature and pressure on the pressure produced by a Pitot tube and that this instrument will accurately reflect the true air speed .for all conditions oi. atmospheric temperature and pressure.- This embodiment of our invention, like the previous embodiment. drives through a floating member and means is provided to vary the rate at which this floating member is dr ven by the main actuating means. Likewise. provision is also made to vary the driving action of the floating member on the fuel valve indicator pointer Or other driven element in accordance with variations inv another moditying condition. Our 'novel rate changing mechanism eflects the requisite compensations through simple and inexpensive structure which may be readily incorporated in a wide variety of devices.

While we' have illustrated and described only two] embodiments of our invention. it is understood that our invention may assume numerous other forms and includes all modifications. variationsand equivalents coming within the scope of the appendedclaims.

We claim:

1. Rate-changing mechanism of the class described, comprising a driving element, a floating member, slots provided by said element and member, a pin movable; lengthwise of said slots to vary the driving relation' between said element and member, means for shifting said pin length-' wise of said slots, a driven element, slots provided by said member and driven element. a pin movable lengthwise of said last-named slots to vary the driving relationship between said memof said slots to vary the driving relation between said element and member, means for shifting said pin lengthwise of said slots, a driven element, slots provided by said member and driven element, a 'pin movable lengthwise of said lastnamed slots to vary the driving relationship between said member and s d driven element, said pins being independent 0 each other, and separate means for shifting said last-named pin.

3. Rate changing mechanism of the class described, comprising a driving element, a floating member, a pair of pivots therefor, slots provided by said element and member, a pin movable lengthwise of said slots to vary the driving relation between said element and member, means for shifting said pin lengthwise of said slots, a driven element, slots provided by said member and driven element, a pin movable lengthwise of,

said last-named slots to vary the driving relationship between said member and said driven element, said pins being independent of each other, and separate means for shifting said lastnamed pin.

4. Rate changing mechanism of the class described, comprising a driving element, a floating member, slots provided by said e'lement and member, a pin movable lengthwise of said slots to vary 'the driving relation between said element and member, pressure-re ponsive means for shifting said pin lengthwise of said slots, a driven element, slots provided by said member and driven elemerit, a pin movable lengthwise of said lastnamed slots to vary the driving relationship between said member and said driven element, said pins being independent of each other, and separate means for shifting said last-named pin.

5. Rate changing mechanism of the class demeans for shifting said last-named pin, said tem-- perature responsive means being independent of said first named shifting means.

6. Rate changing mechanism of the class de-' scribed, comprising a driving element, a floating member, slots provided by said element and member, a pin movable lengthwise of said slots to vary the driving relation between said element and 7. Rate changing mechanism of the class de-I scribed comprising in combination a driving element in the form of a lever adapted to swing about a horizontal axis and provided with a longitudinally extending slot therein, a plate opposite tosaid lever and movable vertically with respect thereto but held from angular movement and provided with a horizontal slot therein op-' posite to the slot in said lever, a horizontally dis- DOSedpin engaging said slots and movable toward and from the axis about which said lever is movable, means for controlling the position of said pin, .a, driven element in] the form of a lever adapted to swing about a horizontal axis adjacent to said first-named lever and provided with a ion-f gitudinaliy extending slot therein, said plate being provided also witha second horizontal slot Qtherein oppositeto the slot in said second-named lever, a second horizontally positioned pin engaging said last-named slots and movabl toward and from the axis about which said second lever I is movable, and means for controlling the position of said second pin.

.8. A device for regulating iio w'of fuelto a fuel consuming device comprisingin combination a lever adapted to swing about a horizontal axis andprovided with a longitudinally extending slot .said slots and movable toward and from the axis about which said leveris movable, air pressure responsive meansfor moving said pin along said slots, a driven element in the form of a lever adapted to swing about a horizontal axis adjacent to said first-named lever andprovided with a longitudinally extending slot therein, said plate being provided also with a second horizontal'slot lever, a second horizontally positioned pin en-.l gaging said last-named slots and movable toward member, atmospheric pressure responsive means for shifting said pin lengthwise of said slots, a driven element, slots provided by said member and driven element, a pin movable lengthwise f- 8 V is movable, temperature responsive means for moving said second pin along said last-named slots, and a fuel valve controlled by the movementsofsaid second lever. V

a 9. Rate changing mechanism of the class described, comprising in combination two brackets 1 in spaced relation, a driving element in the form of a lever adapted to swing about a horizontal pivot pin mounted on said brackets and provided with a longitudinally extending slottherein, two plates between said brackets at opposite faces of said lever and provided with horizontal slots therein opposite to the slot in said lever, pivoted links connecting said plates with said brackets for holding the plates against angular movement while permitting the plates to move freely up and down, a horizontally disposed pin engaging said slots and movable toward and from the axis of thelever, air pressure responsivemeans for moving said pin along said slots, a driven element in the form of a.lever mounted above said firstnamed lever between said plates so as to swing about a horizontal pivot pin carried by said i therein opposite to the slot in said second-named 0 and from the axis about which said second lever:

brackets and provided with a longitudinally extending slot therein, said plates being provided also with horizontal slots therein opposite to the slot in saidsecond narned lever, a second horizontally' positioned pin engaging said last-named slots and movable toward and from the axis of said second lever, and temperature responsive means for moving said second pin along said lastnamed slots. V

' IRWIN E. MATHER. ARTHUR C. ALLEN. STANLEY J. BUDLANE.

REFERENCES CITED The following references are of record in the file of this patent: f

UNITED STATES PATENTS Number v Name Date 2,183,586 Phillips et a1 Dec, 19, 1939 2,251,498 Schwein' Aug. 5, 1941 2,062,110 Swartout Nov. 24, 1936 1,737,746 Young Dec. 3, 1929 2,278,682 Wagner Apr, 7, 1942 2,087,885 Fleischel July 27, 1937" 2,190,506 Wurr Feb. 13, 1940 737,541 I Williams Aug; 25, 1903 1,892,765 Howard Jan.,3, 1933 1,665,145 Peltz Apr.'3, 1928 1,684,500 McKee Sept. 18, 1928 1,707,340 Young Apr. 2, 1929 2,161,743 Heinrich June 6, 1939 893,176 Levilly July 14, 1,908 1,913,684. Purdy, June 13, 1933 2,185,578 Beardsley et al. Jan. 2, 1940 FOREIGN PATENTS Number I Country Date 337,136 Italian Feb. 27, 1936 808,165 French Nov, 6, 1936 

